Spark plug



J. C. ROWAN SPARK PLG vwanoz. JOHN C. ROWAN /WZQQWJ.

Filed Dec. 23 1922 @Noruego Patented June 17, 1924.

UNITED STATES PATENT oF-F'lcE.

JOHN' C. ROWAN', 0F ATLANTA, GEORGIA, ASSIGNOB OF NEHALF T0 WILLIS DOBBS, F ATLANTA,

SPARK PLUG.

Application nled Decemberz, 1922. Serial Nb. 608,593.

To all whom. t may concern.'

Be it known that l JOHN C'. RowAN, a citizen of the United States, residin at Atlanta, in the county of Fulton and tate of Geor 'a, have invented certain new and useful mprovements in S ark Plugs, of which the following is a ull, clear, and exact description.

My invention relates primarily to spark plugs to be used in connection with in" ternal combustion engines and has for its object to provide such a device having a plurality of adjustable spark gaps by means of which the intensity of the spark may be varied, so as to prevent fouling of the plu by superfluous oil and by which the genera efficiency of the motor 1s increased.

A further object of the invention resides in the provision Aof a transparent casing for enclosing the spark gaps, wherebythe operation of the plug may be observed at all times.

Another o'bject of the invention contemplates the use of a portion of one of the y electrodes as a tool for adjusting the spark gaps.

Other objects and advantages of the invention will be apparent from the following description when taken 'in connection with the accompanying drawings, in which,

Figure 1 is a side elevation of the improved spark plug.

Figure 2 is a longitudinal section through the plug.

Figure 3 is an'enlarged fragmentary section through the upper end of the plug, and

Figure 4 is a horizontal section taken on line 4-4 of Figure 3.

Referring to the drawing more in detail the numeral 1 indicates the main body or shell of the plug which is exteriorly threaded at its lower end for securing in the body of the engine. This shell is interiorly threaded as indicated by numeral 2 for the reception of the nut 3 by means ot which the insulating porcelain 4 is clamped in place against the shoulder 5 of the shell 1. Gaskets 6 and 7 are interposed between the porcelain 4 and the nut 3 and shoulder 5 espectively to prevent injury to the porceain.

The upper body of the plug comprises a casing 8 of glass or similar transparent material, preferably of conical form in order to strengthen the same and also to allow for the ready positioning of the usual sparkplug wrench. This casing is formed with The shell 1 has permanently connected.

therewith the inwardly directed electrode 15 which is suitable spaced from the section 16 of the main electrode which is embedded in the insulating porcelain 4. This porcelain is formed with a spherical cavity adjacent its upper end in which terminates the upper end of the main electrode section 16. Threadedly mounted in the bushing 18 carried by the porcelain 4 is the middle section 19 of the main electrode, which is provided with a kerf 20 in its end in order that this section of the electrode may be rotated for longitudinal adjustment.

Threadedly mounted in the ferrule 13 is `a sleeve 21 in which is slidably connected the upper or third section 22 of the main electrode. A coil spring 23 surrounds the lower portion of the section 22 and normally holds the latter at the limit of its outward movement. A pin 24' prevents complete removal of the electrode section 22 from the sleeve 21. From this construction is is obvious that the point of the section 22 may be adjusted to the proper position by adjusting the sleeve 21 within the ferrule 13, a nut 24 being provided for locking the sleeve 21 in adjusted position. A cornesponding adjustment may be made of the intermediate section 19 by pushing downwardly on the section 22 until its sharpened end 25 engages the kerf 2O in the electrode section 19, and then turning the section 22 in the proper direction by means of its knurled end 26.

A nut 27 is threaded to the sleeve 21 for the purpose of securing the usual line wire (not shown) in electrical engagement with the plug.

In operation, if it is desired to change the lengthy of the llower spark gap in the main electrode, it is only necessa to `press inwardly on the'section 22 until lts end 25 engages in the kerf 20 and then turn the same in the required direction. The engagement of the parts 20 and 25 and the adjustin operation may, of course, observed t rough the transparent casing 8. For ad'usting the position of the main electrode t e nut 24 is loosened and the sleeve 21 turned in the proper direction to move the point 25 to the desired position.

From the foregoing description it will be seen that I havev provided a spark (plug having comparatively few parts an in which adjustable spark gps are lprovided for intensifying the spar Also that the ad'ustments of these ga s may be made in full view and without t e aid of tools.

In accordance with the patent statutes I have described what I now believe to be the best embodiment of the invention, but I do not wish to be understood thereby as limiting myself or the scope of my invention as many chan es and modifications may be made thereln without departing from the spirit of the invention, and all such I aim to include within the scope of the appended claims.

What I claim as new and desire to secure by Letters Patent is: l

1. In a spark plug, a sectional electrode including a spark gap, one of said sections being longitudinally adjustable, and another of said sections being constructed and arranged for operating the adjustable section. l

2. In a spark plug, a sectional electrode including a plura ity of spark gaps, two of said sections being adjustably mounted, and

' cooperating means on said adjustable sec- ,tions whereby one of said Asections may be adjusted by the other section.

3. Ina spark plug, a sectional electrode including a plura ity of spark gaps, one of said sections being longitudinally adjustable, means on another of said sections for adjusting the adjustable section, and resilient means normally holding said sections apart. 4.-. In a spark lug, a sectional electrode includin a plura ityof spark gaps, two of said sectlons being adjustably mounted, coopprating means on said adjustable sections w ereby one section may be adjusted throu h the other section, and a coil spring encirc ing one of said adjustable sections and normally holding it inretracted position.

5. In a spark (plug, an electrode comprising three space longitudinally arranged sections, means for adjustably mounting the central section, means for adjustably mounting the upper` section, said latter means including a sleeve adjustably mounted in the upper end of the plug and in which said upper section is longitudinally movable, cooperating means w ereby one of said adjustable sections may-be operated by the other adjustable section, and means normally holding said adjustable sections spaced apart.

6. In a spark plug, a sectional electrode including a spark gap, one of said sections being longitudinally` adjustable, another of said sections being constructed and arranged for operating said adjustable section, and a transparent casing surrounding the portion of the electrode mcluding the spark gap, whereby the manipulation of one section by the other may be observed.

JOHN C. ROWAN. 

